On the subject of taking roach on the drop; Last year i came across a book by Capt L A Parker (I think that is correct!) well known for his big roach catches. In the book he mentioned 'The Wooden Ledger', something he had developed (from memory) which offered vertually zero resistance to a taking fish on the bottom (in his opinion).
The set up consisted of a short length of dowelling (3/4" or so) which is held in position by shot either side with just enough weight to allow it to drop slowly through (still) water to eventually rest on the bottom.
i made up some sealed balsa dowels with a tiny hole to take the line which I used (generally) 2/3' from the hook on very light bottoms. It was a case of casting out underarm with single maggot on the hook 'handlebar fashion' (more natural when dropping through the water when tested in shallow water) and watching the point where line met the water for bites.
Now I'm not saying I caught dozens of big roach but I did catch and what suprised me was the fact that most fish were taken 'on the drop' with fish up to 3/4lb or so and if the bait did reach bottom I then used a very light bobbin for bite detection which, generally speaking, were positive and mostly difficult to miss. I also tried repeat casting once the bait hit bottom (the sinking line stopped moving!) and this also caught fish.
Conditions (when most successful) were sunny calm days.
Nothing new in fishing but this method was new to me after 60 years fishing and it made a pleasant change to try something different. I'm no genius around the 'neutral density' side of this method ( from memory) suggested by Parker but to my mind it has merit and if the quality of bies was anything to go by the fish felt little resistance........Others may have an opinion on this!
So, if the original poster wants to try something a little different it may well prove to be the answer to his missed bites-no promises though!!
For the record I used various sizes of balsa dowelling for experimenting purposes but started with a piece 1/2" dia x 3/4" long which I stained brown and sealed with dope and a light varnish and this caught fish. The rate of decent through the water was very slow if time was spent adjusting the shot and in my opinion this was critical.....
I will be trying this again this season as I think it may well prove successful for better roach but taht remains to be seen......
The maggot hooked sidways with a light scattering of freebies also helped (in my opinion).................................