Helix Syn: help with sweet spot, contractions, and lube

I’ve had the Helix Syn for 5 months and have about 15 sessions. I’ve had some success with milestones such as pleasure through contracting, feeling the prostate, sometimes on the sweet spot, occasional involuntary muscle contraction, overall enjoyment, jerking, pleasure by blood pulses internally, and moaning during the sessions.

I’m feeling blocked, although i’ve spent a dozen hours reading wiki and forum posts for ideas. I seem to be the most successful while standing or sitting / over slouched on the couch with my butt hanging from the edge. Challenges:

1. I’m unsure where my Sweet Spot is. I’ve tried the tests in the Wiki, but I can’t seem to nail down. Sometimes during a session I reposition the p-Tab and know it’s the right place, because I immediately begin involuntary muscle contraction, but soon quit if the p-TAB moves. I try to secure it with my fingers, but it moves and I lose track of the right position and have trouble to find it again.

2. I often get the most pleasure from the combination of moderate to severe rectal contractions with anal and clower pelvic/kegel contractions. But pleasure seems mostly to come from when the Aneros comes out and the p-tab is an inch or two from my perinium. As if my body wants to push it in and out, but if I’m not careful it ejects and I have to keep a hand there to keep from coming out. Does this mean that my prostate is more shallow than the Helix Syn and I should try another model?