VG's on the UNDERSIDE of the hor stab, about 1.5" in front of the stab/elevator gap can increase the available elevator authority. In fact most certified vg's kits come with them for the stab, besides the wing tops. The wing ones let you attain a bit higher AOA before stalling and the enhanced elevator authority let you take advantage of that. Gap seals between the hor stab and elv, can also increase it's power, sailplane parts suppliers are a good source. Is your hor stab AOA adjustable? If so, set right?
I dealt with poor elevator authority in the flair with my first RANS S-7, which I installed a converted Subaru engine in, much heavier then it was designed for. Reliable as hell, 1300 hours and no problems, but unless it was loaded for XC or with a passenger, I was always on the verge of too far forward CG, even after adding lead in the tail. The above mentioned mods helped that condition.
Your static stick rigging should be based on how many degrees of movement you have in the control surfaces, set while on the ground.....not as a way to solve poor pitching power in the flair, ideally anyway! See if you can get a shot of your elevator in level flight/cruise, it should be in line with your hor stab for best performance.