Mel. I ride my horse like that (at least for years on trails). I took H/J and Dressage lessons--and western. Trailriding especially for hours is different. My Daughter is a H/J instructor. She rode a forward seat once with me at a clinic for about 15 miles and liked to died. Her lower back was really hurting,k because they lean forward--hence "forward seat".
H/J and dressage people often use the reins as part of balance. Just like the Western sort of jam themselves into their stirrrups and up against the cantle.
My arab doens't like tight contact either-- I ride a modified english, in a hybrid saddle now.(have used , endurance, western, and aussie)
To help with your posting and balance, get in a ring of sorts .(can use rope or tape on trees or posts) (for safety) .Don't TRY to post with a big T. Let your horse push you up. try to post with as small a lift as possible. You usually need a hands width between your fanny and the saddle standing in your stirrups . But you don't have to post this high. Say "up, down" as your practice till the rhythm is natural for you and you don't need the words. You want to go up on the outside shoulder as the leg reaches forward, and down as it goes back. You can put a spot or piece of tape on the horses shoulder to help. Practice 10 times one direction , then 10 times the other direction. Your horse will catch on to the lap thing fairly quickly. You can do this on a fairly loose rein.
Next try to drop your stirrups and do it without stirrups, This will really help your balance. Many people shove from their stirrups , but it should actually come from the the upper leg /hip.Post forward and up slightly , let your horse push you up.Straight up and down will make you fall behind the rhythm most likely in the beginning. Don't lock your hip or lower back. Think of being JELLO there. Don't hold your self up too long. Try to get with his rhythm, it helps if you can keep him a specific speed trot, (a good working trot helps). And different horses have different posts. Mine is quick and low, which I like, but get me on a long, tall horse and it takes me a while to adjust. I once rode a X dressage horse, and they made me use about 25 lbs. of pressure on the reins and he bounced me so hard , I had to get off and go the bathroom , frequently;0() -- This was not a fun horse to ride!!!! He also took a 2.4 jump at about 3.6", (my only 3.6" mind you!!!)--
Try not to be stiff or lock any joints. Clinton Anderson was just saying that the riders with the best balance were english riders, because they had to learn to post and posting will really help your balance.
Also the "kick in rhythm " thing.Call it "lets annoy the horse ". This is one of those carry over things everyone does, cause everyone does. No , not all h/J trainers teach this. Often it is for a plug or school horse, I rode a couple of those, (really didn't like them, no go, no sensitivelty) who won't keep moving. Or they think it will keep them in rhythm. Or "it is always taught this way".-- All you are doing , is nagging the horse, till they are "dead sided". Since my horse was trained that leg bumping means something like move over or go forward, that is what he does, I stop (release pressure, when he does what I want). Otherwise you burn the cue, and it is no longer a cue, it is a meanlingless aggravation. Hanging on his mouth will make him less sensitive to real cues, so you will have to use more pressure etc. and on it go.
Trail riding lots is different from ring riding. Some methods an't be sustained comfortable on long rides. You can do a lot of things for 5-15 minutes that won't translate to the trail.
Have fun!
